Reflector type incandescent or gas discharge-electroluminescent lamp



July 31, 1956 A. H. LAIDIG 2,757,300

REFLECTOR TYPE INCANDESCENT OR GAS DISCHARGE-ELECTROLUMINESCENT LAMP Filed Oct. 1, 1953 2 Sheets-Sheet 2 m-ascmve ELECT/200E 44 mmvsrmeovr err/ewe 36? United States Patent REFLECTOR TYPE INCANDESCENT 0R GAS DIS- CHARGE-ELECTROLUMINESCENT LAMP Alfred H. Laidig, Bloomfield,N. 1., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 1, 1953, Serial No. 383,449

9 Claims. (Cl. 313-3) This invention relates to lamps, and more particularly, to reflector type incandescent or gas discharge-electroluminescent lamps.

Heretofore reflector type incandescent lamps have been widely used in indirect lighting applications where the direct and reflected light is cast onto a dilfusing overhead ceiling or other diffusing means, or in applications where the direct and reflected light is formed into a flood or spot beam, such as in high-bay factory installations. Because of the relatively high power of these incandescent lamps it is impractical to use them as night lights, and it has been customary to provide separate smaller incandescent lamps where night lights are indicated, necessitating separate fixtures, etc.

In addition, it is sometimes desirable to provide a small amount of illumination above the high-bay factory flood lamp, or on the reflector side of the indirect lighting type lamp for general illumination as well as decorative purposes.

It is the general object of my invention to provide a reflection type incandescent-clectroluminescent lamp.

It is another object of my invention to provide a reflector type lamp which may be used for both general illumination and night lighting purposes.

It is a further object of my invention to provide a reflector type lamp which has two separate light sources which emanate light from separate portions of the lamp envelope, so as to produce an illuminating beam in one direction and a guiding or locating beam in the other direction.

It is still another object of my invention to provide a reflector type lamp in which the reflector portion is illuminated for decorative purposes.

It is a still further object of my invention to provide a reflector type gas discharge-electroluminescent lamp.

The aforesaid objects of the invention and other objects which will become apparent as the description proceeds are achieved by providing a combination reflector type incandescent or gas discharge-electroluminescent lamp wherein the lamp reflector simultaneously serves as one electrode for the electroluminescent portion of the lamp.

For a better understanding of the invention reference should be had to the accompanying drawings wherein:

Fig. l is an elevational view, partly in section, illustrating a preferred embodiment of my invention;

Fig. 2 is a sectional view on the line II--II of Fig. l, in the direction of the arrows, illustrating the electrical connection to one electrode of the electro-luminescent portion of the lamp;

Fig. 3 is a fragmentary enlargement of a section of the electroluminescent portion of the lamp on the line III-III of Fig. l, in the direction of the arrows;

Fig. 4 is an elevational view, partly in section, representing an alternative embodiment of my invention and illustrating an energizing circuit which enables the lamp to be used either as a conventional illuminating source or as a night light;

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Fig. 5 is a sectional view on the line V--V of Fig. 4, in the direction of the arrows, illustrating the electrical connection for the electroluminescent portion of the lamp;

Fig. 6 is an elevational view of an alternative embodiment of my invention, wherein the electro-luminescent portion of my lamp is placed on the outer surface of the lamp envelope;

Fig. 7 is a fragmentary enlargement of the base portion of the lamp on the line VIIVII of Fig. 6, in the direction of the arrows, illustrating the electrical connections for the electroluminescent portion of the lamp for this embodiment.

Fig. 8 is a fragmentary enlargement of a portion of the envelope on the line VIII--VIII of Fig. 6, in the direction of the arrows;

Fig. 9 is an elevational view, partly in axial section, of a further alternative of my invention;

Fig. 10 is an elevational view, partly in axial section of yet another embodiment of my invention, wherein the incandescent light source is replaced by a gas-discharge light source;

Fig. 11 is a fragmentary enlargement wherein the separate phosphor and dielectric layers are interchanged from the embodiment as shown in Fig. 8;

Although the principles of the invention are broadly applicable to any reflector type lamp, the invention is usually employed in conjunction with reflector type lamps as used in indirect lighting or in spot and flood lighting for high-bay factory installations nad other similar applications, and hence it has been so illustrated and will be so described.

With specific reference to the form of the invention illustrated in the drawings, the numeral 12 indicates the lamp generally, comprising an envelope consisting of a bulb portion 14 and a neck portion 16 and having a reentrant stem 18 hermetically sealed to the envelope neck portion'14.

The reentrant stem 18 comprises a press portion 20, flare portion 22, which is sealed to the envelope neck, and lead-in conductors 24 and 25 sealed through the stem press. A tipped-oil exhaust tubulation 26 is also included, as is usual in the lamp art. The lead-in conductors 24 and 25 extend inwardly within the envelope and support a primary light source between their inward extremities, which primary light source preferably con sists of a refractory metal filament 28, as illustrated.

An electrical contact adapting base, which comprises a shell portion 30 and an eyelet 32 insulated from the shell, is attached to the envelope neck portion 16. One of the lead-in conductors 25 makes electrical contact with the eyelet 32 and the other lead-in conductor 24 makes electrical contact with the base shell 30 which shell and eyelet are adapted for making electrical contact with a source of electrical energy (not shown).

In such an incandescent lamp, as described, which lamp is normally mounted in a base-upward position and is quite common, the lead-in conductors may be of copper or nickel-plated iron. The filament 28 may be fabricated of tungsten and the envelope and reentrant stem of soft glass. The portion of the lead-in conductors which pass through the stem press 20 may be provided with a sheath of copper to facilitate sealing, as is common. The lamp base shell 30 and eyelet 32 may be fabricated of brass and the lead-in conductors may be soldered to these to make electrical contact. As is common, the lamp envelope may be evacuated or may enclose a substantially oxygen-free inert gas atmosphere at reduced pressure.

The reflector portion of the lamp is coated over that portion of the envelope which is located opposite the lamp base and this reflector is desirably extended along the envelope bulb toward the base so that direct light from the filament which is emanated in a substantially horizontal direction will be reflected by the reflector portion toward an overhead diffusing medium (not shown). That portion of the envelope over which the reflector is applied constitutes a foundation glass for an auxiliary light source comprising an electroluminescent lamp 34, which lamp may be fabricated on the inner surface of the envelope bulb as illustrated in Figs. 2 and 3.

The electroluminescent lamp may consist of a first conductive layer 36 coated on and adhering to the envelope bulb inner surface with a phosphor-dielectric layer 38 consisting of a phosphor 40 embedded in a dielectric 42 coated thereover and adhering thereto. A second electrically conductive, opaque, reflective layer 44 is coated over and adheres to the phosphor-dielectric layer 38 to complete the electroluminescent lamp.

As shown in Fig. 1, a narrow strip 45 of the first electrically conductive layer 36 is extended toward the base portion of the envelope in order to facilitate electrical contact for the electroluminescent lamp. The phosphordielectric layer 38 is coated over only that portion of the envelope which is to be made reflective in nature and the reflective electrode 44 is coated over this phosphordielectric layer 38. Electrical contact for the electroluminescent portion of the lamp may be made by electrically connecting each of the electrodes 36 and 44 with lamp lead-in conductors 24 and 25. Electrical contact may be made between one of the lead-in conductors 24 and the light-transparent electrode 36 by means of a first spring electrical contact adaptor 46 which is directly attached to the lead-in conductor and which automatically makes electrical contact with the narrow basewardly extending strip 45 of first electrode 36 when the lamp is fabricated.

Electrical contact between the other lead-in conductor 25 and the reflective electrode 44 may be made by means of a second spring electrical contact adaptor 48 which is preferably fabricated in part in the shape of a helical spring in order to maintain compression and electrical contact between the lead-in conductor 25 and electrode reflector 44. An enlarged extremity 49 for adaptor 48 may be provided, if desired, to insure good electrical contact.

The first electrically conductive layer 36, i. e. the layer which is adjacent the inner surface of the envelope bulb, must be transparent as heretofore noted, and should preferably be relatively thin. In the embodiments as illustrated, this layer may be fabricated of tin oxide of a thickness of about 0.00006 cm., if desired, although this thickness is in no way critical. The first layer 36 may be applied by Well-known vacuum-metallizing techniques, then passing a warm stream of oxygen over the coating to convert the thin coating to the transparent oxide. In vacuum metallizing the coating metal is placed on a tungsten boat or filament and the boat and object to be coated are placed in a partial vacuum. On heating the boat to the boiling point of the coating metal, a thin metallic film is deposited. Other metals such as zinc, cadmium, antimony, or bismuth may be substituted for the tin.

The phosphor 40, which is embedded in the dielectric 42 to form the phosphor-dielectric layer 38, may be a mixture of field-responsive zinc oxide and zinc sulfide, activated by copper, as indicated on page 710 of New phenomenon of electrophotoluminescence," by G. Destriau, Philosophical Magazine, October 1947, vol. 38. As an example, the 75% zinc oxide, 25% zinc sulfide, copper activated phosphor, as indicated by Destriau, may be used if desired.

The dielectric 42 must be light transmitting, have a relatively high dielectric constant and must not deform at those temperatures to which the reflector of a reflector type lamp is subjected. Experience has indicated that the envelope on which the reflector is coated is ordinarily subjected to temperatures which may vary between about 75 C. to 150 C. and dielectrics which will withstand these temperatures may be used. There are numerous types of dielectrics which will meet the foregoing requirements and withstand even the highest temperatures to be encountered, e. g. 200 C., an example being a lighttransmitting polymonochlorotrifluoroethylene, as marketed by M. W. Kellogg, Jersey City, N. 1., under the trade mark KelF.

Also satisfactory as a dielectric would be light-transmitting polytetrafluorethylene compounds, an example of such a compound being marketed by E. I. Du Pont de Nemours & Co., Inc., Wilmington, Delaware, under the trade mark Teflon. A further possible general class of compounds which could be used as the dielectric are phenyl-methyl silicones having an organic group to silicone ratio of approximately 1.5 to 1. Such compounds are marketed as varnishes by several commercial suppliers under the general descriptive term, silicones.

There is illustrated in Fig. 4 a modification of the lamp illustrated in Fig. 1 which enables my combined incandescent-electroluminescent lamp to be used as a nite-lite, general illumination source, if desired. The base of the lamp is similar to the base as illustrated in the first embodiment, except that it is three-way, with an additional contact 50 provided between the eyelet 32 and the shell 30*, such bases being common in the art. The electrical connection to this base is provided through a three-way switch 52, as is common in the art. This embodiment of my invention differs only from the preferred embodiment in that three lead-in conductors 24 25 and 53 each connect with one of the electrical contact adaptors on the base, and a modified electrical contact means is provided for the electroluminescent portion of the lamp, which modified contact means is illustrated in Fig. 5. The reflector or second spring electrical contact adaptor 48 is connected to a third or individual leadin conductor 53.

The first spring-type electrical contact adaptor 46 is connected between the basewardly extending conducting strip 45 and the lead-in conductor 24 which lead-in conductor also connects to one end of the incandescent filament. The other lead-in conductor 25 is connected to the other end of the incandescent fialment 28. The switch 52 is of such a design that a potential may be applied simultaneously across only two of the lead-in conductors or across all three lead-in conductors, in order to enable the electroluminescent portion and the incandescent portion of the lamp to be energized either simultaneously or individually.

There is shown in Fig. 6 a further embodiment of my lamp which corresponds to the embodiment illustrated in Fig. 1, except that the reflective and electroluminescent portions of the lamp are placed on the exterior surface of the lamp envelope' The electrical connections for the electroluminescent portion of this embodiment are illustrated in Fig. 7 and an enlargement of the electroluminescent portion of the lamp is shown in Figs. 8 and 11. The electrically conductive layer 44 which is positioned adjacent to the lamp envelope bulb 14 is opaque and reflective in nature, and is connected to the base shell 30 by means of a thin conducting lead 56.

Over this reflective layer 44 are coated separate layers of phosphor 40 and dielectric 42 to form a composite phosphor-dielectric layer 38*, and a thin transparent tin oxide layer 36 is coated over and adheres to the composite phosphor-dielectric layer 38. The thin, transparent, electrically conductive layer 36 is electrically connected to the lamp base eyelet 32 by an insulating connecting lead 54, as illustrated in Fig. 7. If the electrode 36 is maintained at ground potential, as may be accomplished by polarizing the plug adapter (not shown) it is not necessary to insulate this electrode from possible contact by the user of the lamp. In the average case, however, the lamp plug adaptor will not be polarized and an additional transparent insulating coating 58 may be provided to pro tect against shock hazard, which coating may be of a silicone, as heretofore described. It should be noted that mechanical basing, which is well-known in the art, has been used in the embodiment of the base illustrated in Fig. 7, in order to facilitate basing and electrical connection for lead-in conductor 24. Such mechanical basing is not absolutely necessary, however, and a conventional base using a basing cement is satisfactory.

There is shown in Fig. 9 a further possible alternative embodiment of my lamp which is designed to be mounted in a base downward position, and whch has application particularly in a high-bay factory and similar installations. In such an embodiment the reflective coating and the electroluminescent portion of the lamp may be coated over nearly all of the envelope except the transparent envelope end 60, and the electroluminescent portion of the lamp may be identical to that shown in Fig. 1, except for the electrical connections. The electrical connection to the electroluminescent portion of the lamp may be made by two spring contact adapters 62 and 64 which electrically connect the individual electroluminescent electrodes with the lead-in conductors 24 and 25.

As yet another alternative embodiment of the invention, there is illustrated in Fig. 10 a lamp wherein the incandescent filament is replaced by a gas-discharge light source which may be a mercury-vapor lamp as is wellknown in the art. Such an embodiment is similar to the embodiment as illustrated in Fig. 9 except that the incandescent filament is replaced by a mercury vapor gas-discharge light source 64. In such a lamp the re-entrant stem press 18 and lead-in conductors 24 and 25 are slightly heavier than the corresponding elements in an incandescent lamp in order to accommodate the greater weight of the discharge light source or tube. Supported by the leadin conductors 24 and 25 is the gas-discharge tube or envelope 66 which is preferably fabricated of quartz and which may have the configuration of a hollow, doubleended cylinder closed at its ends. Such an envelope 66 is enclosed entirely within the lamp envelope which carries the electroluminescent portion of the lamp. Contained within the quartz envelope 66 is a charge of inert, ionizable, starting gas and a small quantity of mercury, as is common in such lamps.

Electrodes 68 are supported at either end of the inner envelope 66 and the lead-in conductors 24 and 25 electrically connect the electrodes 66 with an electric power adapting base (not shown) which may be substantially the same as in the embodiment illustrated in Fig. 9. These electrodes may each take the form of a coiled tungsten filament carrying a coating of alkaline earth oxides. An auxiliary electrode 70 is also provided to facilitate starting, as is well-known in gas-discharge lamps.

The electrical contact for the electroluminescent portion of this embodiment illustrated in Fig. 10 is as illustrated and described in the embodiment as represented in Fig. 9, wherein spring type adaptors 62 and 64 connect the lead-in conductors 24 and 25 with the two electrodes of the electroluminescent portion of the lamp.

It should be noted that in any of the embodiments as illustrated, the phosphor may be either embedded throughout the dielectric, or the phosphor and dielectric may be applied in separate layers. It does not matter whether the separate phosphor layer or dielectric layer lies adjacent to the envelope bulb. Such a possible modification is illustrated in Fig. 11 wherein the dielectric layer 42 is positioned interiorly of the phosphor layer 40 In fabricating the embodiments shown in Figs. 1, 4, 9 and 10, I first form the electroluminescent portion of the lamp on the envelope. The electrically conductive layer which is adjacent the envelope wall is first formed by the method as heretofore described, namely, the vacuum metallizing process. If the phosphor is to be embedded in the dielectric, the phosphor and dielectric are first thoroughly mixed. If the dielectric consists of polymonochlorotrifluoroethylene, for example, the mixture of phosphor and dielectric may be dispersed in a volatile vehicle .such as xylene which is sprayed over the first electrically conductive coating. After drying out the vehicle, the phosphor-dielectric is baked at a tem perature of about 246 C. in order to cure the dielectric. It is preferable that the surface be slightly roughened in order to enable the dielectric to better adhere and this may be accomplished, if desired, by etching the glass envelope before applying the first electrically conductive coating. It it isdesired to use silicones as the dielectric, the phosphor impregnated silicone varnish is sprayed, flushed or painted onto the bulb and the resulting coating is cured by baking it at approximately 250 C. for about eight hours.

If the phosphor and dielectric are to be applied in two separate layers, the dielectric may be applied in exactly the same manner as heretofore outlined, where the phosphor is embedded in the dielectric. The separate phosphor layer may be applied by dusting or by suspending the phosphor in a medium of nitrocellulose and butylacetate and baking out the nitrocellulose binder, or by other conventional means of applying a phosphor coating to a surface. Of course, it is necessary to mask, with masking tape or other suitable masking means, the portion of the envelope which it is not desired to coat and these masking techniques may be utilized in applying both of the electrically conductive coatings and the phosphordielectric coating.

The reflecting electrode may be applied by vacuum metallizing techniques in which the metal to be coated, e. .g. aluminum, is placed on a tungsten or other refractory metal filament. The envelope and metal bearing filament are then placed in a partial vacuum, and the filament heated. Upon heating, the aluminum rapidly vaporizes in a thin even coating onto the surrounding areas, which coating may be of a thickness of about .001 cm. or less.

In fabricating the electroluminescent portion of the embodiment of my invention as illustrated in Fig. 6, the reflective electrode 44 is first applied to the envelope bulb 14 by the heretofore discussed vacuum metallizing techniques, masking by conventional techniques those portions of the envelope which it is not desired to coat. The phosphor and dielectric are then applied over the first reflective electrode 44 as a separate phosphor layer 40 and separate dielectric layer 42. The dielectric is applied as heretofore outlined where the phosphor is embedded in the dielectric. The phosphor may be separately applied by dusting or suspending the phosphor in a medium of nitrocellulose and butyl acetate and baking out the nitrocellulose binder, or by other conventional means of applying a phosphor coating to a surface.

It may be desirable to provide a small electrical contact area 72 on the envelope bulb 14, as shown in Figs. 6 and 8, in order to facilitate electrical connection of the connecting lead 56 to the thin transparent electrode 36. Such an electrical contact area 72 may be formed by painting the envelope portion to which connection is to be made with a silver powder suspended in a binder of nitrocellulose. The paint is then baked at 500 C. to bake out the binder, and the baked silver is copper plated by conventional plating means, to which copper plate the connecting lead 56 can be soldered. In such a construction the dielectric layer 42 at the electrical contact area necessarily extends a short distance further down toward the neck of the bulb than the electrode 44 which is adjacent the envelope. The other electrode 36 necessarily extends a short distance further down the neck of the envelope than the dielectric so as to contact the electrical connection area 72. Since the dielectric layer 42*- completely covers the electrode 44 adjacent the envelope, including the bottom extremity of this electrode, the two electrodes 44 and 36 are insulated from each other, even though the electrical contact area 72 is formed on the envelope bulb 14.

In fabricating the thin transparent electrode which is coated over the phosphor dielectric, as illustrated in Figs. 6, 8 and 11, a very thin coating of metallic tin is applied by the heretofore mentioned well-known vacuum metallizing techniques over the phosphor-dielectric, masking such portions of the lamp as it is not desired to coat. A stream of warm oxygen is then passed over this very thin layer of tin in order to convert it to the transparent oxide. Other metals such as zinc, cadmium, antimony or bismuth can also be used to produce this thin, transparent, conductive layer 36*, first applying thern'by the vacuum metallizing process and oxidizing the resulting thin coating with a warm stream of oxygen. The thin, transparent, insulating coating 58, which as heretofore noted may consist of a silicone, is then painted over the thin, transparent electrode 36 and that portion of the connecting leads 54 and 56 which it is desired to insulate.

After the electroluminescent portion of the lamp has been formed, the prefabricated reentrant stem press 18 is inserted into the neck 16 of the envelope and'the stem press flare 22 is sealed to the base of the envelope neck. In the case of the embodiments shown in Figs. 1, 4, 9 and 10, electrical connections for the electroluminescent lamp will be automatically made by the spring type contacts upon orientation and insertion of the stem press into the neck. In the case of the embodiment as shown in Fig. 6, electrical contact between the electroluminescent portion of the lamp and the electrical contact adaptor base can be made when the base is attached to the lamp neck. In sealing the stem press flare 22 to the lamp neck 16, it is necessary to use relatively high temperatures in order to satisfactorily fuse the glass. To prevent damage to the electroluminescent portion of the lamp during this sealingin process, an automatic heat baflle as described in the copending application of Mortimore Eber and J. A. Storms, Serial No. 339,376, filed February 27, 1953, now Patent No. 2,691,850, and assigned to the present assignee may be utilized. The lamp is then evacuated through the exhaust tubulation, inert gases are inserted, if desired, and the exhaust tubulation is tipped off, as is common in the lamp making art. The lamp base is then attached to the neck of the lamp by basing cement, as is customary, and the lead-in conductors are soldered to the lamp base shell and eyelet. Of course, if mechanical basing is utilized, no basing cement is necessary. It should be noted that such a lamp, as illustrated and described, is particularly adapted for use with the type of electroluminescent phosphors which may be further sensitized when operated in a vacuum as disclosed in copending application Luke Thorington, titled Electroluminescent Cell and Luminescent Material Therefor, Serial No. 276,421, filed March 13, 1952, and owned by the present assignee.

It will be recognized that the objects of the invention have been achieved by the provision of a reflector type incandescent or gas discharge-electroluminescent lamp which may be used both for general illumination and night-light applications or for decorative purposes.

There is disclosed in copending application E. G. F. Arnott, titled Incandescent-Electroluminescent Lamp, filed concurrently herewith, Serial No. 383,662, an incandescent-electroluminescent lamp wherein the brilliancy of the electroluminescent portion of the lamp is increased by the heretofore unused infrared radiation generated by the primary light source. It should be understood that this increased electroluminescent brilliancy may also be realized in my design, for the electroluminescent portion of the lamp is normally in receptive proximity to the filament in order to receive infrared radiation. It should be noted that the temperatures of the electroluminescent lamp portion in my invention are not quite as high as those encountered in the heretofore noted Arnott application since the innermost electrode in my invention is reflecting in nature and will thus reflect some of the infrared radiation.

While in accordance with the patent statutes one best 8 known embodiment of my invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

v I claim:

1. A reflector type lampcomprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said primary light source being located within said envelope, said electroluminescent lamp comprising a first electrically conductive layer coated on and adhering to said envelope, a field-responsive phosphor and a light-transmitting dielectric coated over and adhering to said first electrically conductive layer, a second electrically conductive layer coated over and adhering to said phosphor-dielectric, one of said electrically conductive coating being positioned interiorly of the other of said coatings, the said interiorly positioned coating being opaque and. reflective in nature, and the other of said electrically conductive coatings being light-transmitting.

2. A reflector type lamp comprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said primary light source being located within said envelope, said electroluminescent lamp comprising a first electrically conductive layer coated on and adhering to said envelope, a field-responsive phosphor embedded in a light-transmitting dielectric coated over and adhering to said first electrically conductive layer, a second electrically conductive layer coated over and adhering to said phosphor-dielectric, one of said electrically conductive coatings being positioned interiorly of the other of said coatings, the said interiorly positioned coating beng opaque and reflective in nature, and the other of said electrically conductive coatings being light-transmitting.

3. A reflector type lamp comprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said primary light source being located within said envelope, said electroluminescent lamp comprising a first electrically conductive layer coated on and adhering to said envelope, a field-responsive phosphor coated over and adhering to said first electrically conductive layer, a light-transmitting dielectric coated over and adhering to said field-responsive phosphor, a second electrically conductive layer coated over and adhering to said light-transmitting dielectric, one of said electrically conductive coatings, being positioned interiorly of the other of said coatings, the said interiorly positioned coating being opaque and reflective in nature, and the other of said electrically conductive coatings being light transmitting.

4. A reflector type lamp comprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said primary light source being located within said envelope, said electroluminescent lamp comprising a first electrically conductive layer coated on and adhering to said envelope, a light-transmitting dielectric coated over and adhering to said first electrically conductive layer, a field-responsive phosphor coated over and adhering to said light-transmitting dielectric, a second electrically conductive layer coated over and adhering to said field-responsive phosphor, one of said electrically conductive coatings being positioned interiorly of the other of said coatings, the said interiorly positioned coating being opaque and reflective in nature, and the other of said electrically conductive coatings being light transmitting.

5. A reflector type lamp comprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said primary light source being located within said envelope, said envelope having an exterior and an interior surface, said electroluminescent lamp comprising a first light-transmitting electrically-conductive layer coated on and adhering to said envelope interior surface, a field-responsive phosphor and a lighttransmitting dielectric coated over and adhering to said first electrically conductive layer, and a second electricallyconductive, opaque, reflective layer coated over and adhering to said phosphor-dielectric.

6. A reflector type lamp comprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said primary light source being located Within said envelope, said envelope having an interior and an exterior surface, said electroluminescent lamp comprising a first opaque, reflective, electrically-conductive layer coated on and adhering to said envelope exterior surface, a field-responsive phosphor and a lighttransmitting dielectric coated over and adhering to said first electrically conductive layer, and a second electrically conductive, light-transmitting layer coated over and adhering to said phosphor-dielectric.

7. An incandescent-electroluminescent reflector type lamp comprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said envelope enclosing said primary light source in an inert filling, said primary light source comprising a refractory metal filament adapted to be energized to in-' candesence, said electroluminescent lamp comprising a first electrically conductive layer coated on and adhering to said envelope, -a field-responsive phosphor and a lighttransmitting dielectric coated over and adhering to said first electrically conductive layer, a second electrically conductive layer coated over and adhering to said phosphor-dielectric, one of said electrically conductive coatings being positioned interiorly of the other of said coatings, the said interiorly positioned coating being opaque and reflective in nature, and the other of said electrically conductive coatings being light transmitting.

8. A gas discharge-e1ectroluminescent reflector type lamp comprising an auxiliary electroluminescent lamp fabricated on the envelope of a primary light source, said primary light source being located within said envelope, said primary light source comprising a discharge tube having electrodes sealed therein and adapted for excitation to generate visible light, said electroluminescent lamp comprising a first electrically conductive layer coated on and adhering to said envelope, a field-responsive phosphor and a light-transmitting dielectric coated over and adhering to said first electrically conductive layer, a second electrically conductive layer coated over and adhering to said phosphor-dielectric, one of said electrically conductive coatings being positioned interiorly of the other of said coatings, the said interiorly positioned coating being opaque and reflective in nature, and the other of said electrically conductive coatings being light transmitting.

9. A reflector type lamp comprising, a transparent envelope having a bulb and a neck and a reentrant stem press sealed to said neck, said envelope enclosing a substantially oxygen-free atmosphere, an electrical contact adapting base attached to said neck and having electrical contacts insulated from one another, lead-in conductors electrically connected to said base electrical contacts, sealed through said stem press and supporting a refractory metal filament Within said envelope bulb, said envelope bulb comprising a foundation for an electroluminescent lamp, said electroluminescent lamp comprising a first electrically conductive layer coated on and adhering to said backing plate, a field-responsive phosphor and a light-transmitting dielectric coated over said first electrically-conductive layer, a second electrically-com ductive layer coated on and adhering to said phosphor dielectric layer, said first electrically-conductive layer being electrically connected to one of said base electrical contacts, said second electrically conductive layer being electrically connected to another of said base electrical contacts, one of said electrically-conductive coatings being positioned interiorly of the other of said coatings, the said interiorly positioned coating being opaque and reflective in nature, and the other of said coatings being light transmitting.

References Cited in the file of this patent UNITED STATES PATENTS 2,115,839 Briefer May 3, 1938 2,177,705 Friederich Oct. 31, 1939 2,419,432 Wright Apr. 22, 1947 2,654,042 Clarke Sept. 29, 1953 

